The value of QSM combined with free water imaging in the differentiation of early multisystem atrophy from Parkinson's disease

Motivation: We hope to provide some clinical assistance in distinguishing early Parkinson's disease from early multisystem atrophy. Goal(s): In this study, we investigated alterations in iron deposition in deep grey matter nuclei and free water indicators in patients with early Parkinson's disease and early multisystem atrophy. Approach: We manually sketched the putamen (PT), substantia nigra (SN) and dentate nucleus (DN) to obtain magnetic susceptibility values and free water imaging metrics for each nucleus. Results: We found that DN plays an important role in identifying patients with early PD and early MSA. Impact: This study suggests that QSM and free-water imaging are complementary tools to reveal pathophysiological differences in iron deposition and microstructural changes between early PD and early MSA. Therefore, the combination of both techniques may support differential clinical diagnosis further.